A hypodermic needle has many applications in modern medicine. One application is to fit the hypodermic needle onto a syringe and to then insert the needle into a person's body for intramuscular, subcutaneous, or intravenous injection of medications. A hypodermic needle entering into a patient's body is invariably contaminated by the patient's blood and body fluids. Following use of the needle, the needle presents a risk to physicians, nurses, and other health care personnel because the needle might transmit an infection or disease to such personnel if it were to accidentally puncture them. Thus, health care personnel are in constant danger of contracting infections and diseases, some of which may be deadly. Other potential victims of accidental needle punctures include sanitation workers which later dispose of garbage containing the hypodermic needle. The diseases which may be transmitted by a contaminated hypodermic needle include Immune Deficiency Virus, Hepatitis, Rabies, Kure, Encephalitis, and Arbor viruses. The outcome of contracting one of these diseases is often fatal because there are no known cures for any of these diseases. Often a needle puncture in a person's skin is so trivial that it remains unrecognized until the person becomes seriously ill.
The problem of suffering accidental needle punctures is well recognized. As a result, enormous inventive effort has been devoted to concealing the sharp needle point of hypodermic needles.
The deep-seated central veins, such as subclavian, jugular and femoral veins as well as arteries can only be accessed by negotiating a guidewire, through the puncturing needle, after disconnecting the syringe. The blood gushing out from the needle interferes with the visibility and insertion of the guidewire inside the needle. The blood also contaminates the area of operation and makes the blind insertion procedure even more difficult. The risks of needle stick are further multiplied by free sharp objects, scattered in a limited field. The present invention permits the insertion of the guidewire through the plunger itself without removing the syringe from the needle, as well as making the procedure essentially bloodless. It also avoids the needle puncture by retracting the needle even before it comes out of the patient's body.